Fundamentals of Nutrition Flashcards
Many noncommunicable disease processes are directly associated with _____.
poor nutritional intake
A _____ is any substance providing nourishment essential for growth & life
nutrient
In human metabolism, there are 7 basic types of nutrients that we categorize into three main categories
Macronutrients - Substances we require in large amounts in the diet
■ Carbohydrates ■ Fats ■ Protein
Micronutrients - Substances we require in small amounts in the diet
■ Vitamins ■ Minerals
Other Substances vitally important for digestion and nutrition
■ Water ■ Fiber
A Carbohydrate, or ____, is a molecule consisting of carbon (C), hydrogen (H), and oxygen (O) in various forms of Cx(H2O)y
saccharide
All carbohydrates are composed of _____ molecules
Fructose, Glucose, and/or Galactose
Monosaccharide found primarily in fruits and honey
Fructose
Disaccharide containing fructose and glucose, found in fruits, vegetables, and table sugar
Sucrose
Disaccharide containing glucose and galactose, in dairy products
Lactose
Large polysaccharides chains of glucose, present in almost all non-animal foods (potatoes, corn, grains, rice, etc.)
Starches
4 major forms of dietary carbohydrates:
Fructose
Sucrose
Lactose
Starches
Because of their chemical structures, ____ are not very useful to human cells in their original state
fructose and galactose
Process for breaking down sucrose
The enzyme Sucrase, in the intestinal brush border membrane, is able to separate it into the two monosaccharides, which are then absorbed into portal blood.
Process for breaking down Lactose
The enzyme Lactase, in the intestinal brush border membrane, is able to separate it into the two monosaccharides, which are then absorbed into portal blood.
If levels of ____ get low enough, the intestines are unable to break lactose into monosaccharides.
Lactase
If large amounts reach the large intestine, lactose is fermented by bacteria, producing ____
hydrogen gas
Starch breakdown
- The enzyme amylase is contained in saliva and released by the pancreas into the duodenum.
- It is able to hydrolyse starch into disaccharides and trisaccharides that can then be turned into glucose, which is then absorbed.
A single glucose molecule is metabolized into a total of ____ molecules of ATP. This is through Glycolysis, the citric acid cycle, and oxidative phosphorylation
38
Glycolysis is the first step in this process of breaking down glucose, splitting glucose into ____.
two molecules of pyruvic acid
Acetyl Coenzyme A is then degraded through a series of chemical reactions called the____ (also known as the Krebs Cycle)
Citric Acid Cycle
If the cells become saturated with glycogen, liver and fat cells convert ____ into fat to be stored in fat cells.
excess glucose
In glycogenolysis, Glucose molecules are broken off through phosphorylation, using an enzyme called ____
Phosphorylase.
Phosphorylase must first be activated by either _____ or _____ .
Epinephrine; Glucagon
Fibers are found in plants, forming the leaves, stems, and seeds. Technically, they are a form of ____
carbohydrate
Two types of fiber
- Water-soluble (pectin, gum): slow the passage of foods. Found in oats, peas, beans, apples, citrus fruits, carrots, barley, and psyllium
- Insoluble (cellulose, hemicellulose): increase bulk and speed up food passage through the GI tract. Found in whole-wheat flour, wheat bran, nuts, beans, cauliflower, green beans, and potatoes
Dietary fats are made up of triglycerides, which are lipid structures made of____.
3 fatty acids and a glycerol head
Types of dietary fats
- Saturated: Bacon, milk products, coconut, shortening, most meats
- Trans: Commercial baking goods, fried foods, margarine, shortening
- Monounsaturated: avocados, nuts, olives, peanut butter, seeds
- Polyunsaturated (Omega-3 and 6): seeds, nuts, fish, flaxseed
Globules of triglycerides and cholesterol are packaged up with phospholipids and proteins by the Golgi Apparatus to form _____
Chylomicrons
As Chylomicrons move through capillaries, ____ hydrolyzes triglycerides in the Chylomicron, sloughing off free fatty acids and glycerol.
Lipoprotein Lipase
Once hydrolyzed, free fatty acids (FFAs) and glycerols and are readily absorbed into the capillary epithelium and nearby cells, where they reassemble as ____ and can be utilized by the body
triglycerides
____ is not a fat, but is a sterol (amphipathic lipid) widely distributed in animal tissue.
Cholesterol
TF Cholesterol is fat soluble
T
Cholesterol obtained from the diet is absorbed into _____ along with triglycerides via Chylomicrons
the lacteals of the intestinal microvilli
Excretion of cholesterol occurs ____
through the feces via bile
The liver also produces _____, which are a lipoprotein structure similar to Chylomicrons, but highly packed with triglycerides and cholesterol.
Very Low Density Lipoproteins (VLDL)
The more triglycerides a lipoprotein has, the ____ dense it is.
less
The liver facilitates clearance of ____ from the plasma.
Low Density Lipoproteins (LDL)
As VLDLs circulate, ____ are deposited in tissues (the same way it occurs with Chylomicrons).
triglycerides
______ are primarily responsible for the delivery of cholesterol to the tissues for cellular function.
Low Density Lipoproteins (LDLs)
Because of its association with increased atherosclerotic fatty deposits, ____ is often referred to as the “bad cholesterol.”
LDL cholesterol
____ is capable of removing LDLs from circulation when found in excess with LDL receptor stimulation.
The liver
____ are the smallest and most dense lipoprotein
High-Density Lipoproteins (HDLs)
HDL can participate in _____, meaning they may be able to remove cholesterol from tissues (including arterial walls).
reverse cholesterol transport
There is a statistical decrease risk of heart disease and stroke when patients have higher levels of ____
HDL
ATP production is ____ efficient with fatty acids than the carbs.
more
Proteins from meat and other animal products are complete proteins, meaning they supply all of the_____.
essential amino acids
AAs must be transported across cell membranes (both in and out) via ____ or ____
facilitated transport or active transport using carrier mechanisms
After AAs enter into tissue cells, they combine with one another by ____, directed by the ribosomal system to form cellular proteins.
peptide linkages,
Two forms of protein storage
- Any “storage” that occurs with AAs is basically in the form of actual cellular proteins, such as enzymes, organelles, receptors, etc.
- Large scale storage does not occur, although muscle tissue is a form of “protein storage.”
Some intracellular proteins can be rapidly decomposed into AAs under the influence of ____
lysosomal enzymes.
_____ are degraded and used for energy, stored as fat, or occasionally stored as glycogen
Surplus AAs
Amino acids can be converted into _____.
Acetyl-CoA
The process of degrading AAs occurs almost entirely in the liver and begins with _____, which is the _____.
Deamination; removal of the amino groups from AAs
Ammonia is converted into _____, which is water soluble, and can then be excreted by the kidneys.
urea,
Deaminated AAs are known as _____
Keto Acids
the body can use AAs for energy via conversion of the keto acid into a substrate of the _____
Citric Acid Cycle
_____ is a hormone produced by the fat cells in your body. Its main role is to regulate fat storage and how many calories you eat and burn. It decreases food cravings and increases satiety. It is more related to long term regulation of food intake
Leptin
_____ is produced and released mainly by the stomach. It is a hormone that sends a signal to your brain to feel hungry.
Ghrelin
_____ are non-caloric, essential organic nutrients needed in smaller amounts in the diet.
Vitamins
_____ vitamins are absorbed into the lymph and can be stored in the liver and fatty tissues. Because of this, they can build up to toxic concentrations over time. Periodic doses of these can be sufficient.
Fat soluble
_____ vitamins are absorbed directly into the bloodstream and most are not stored in high quantities. Excess is secreted in the urine. For that reason, frequent intake is more essential and toxicity is less common.
Water soluble
Fat vs. water soluble vitamins:
Fat soluble: Vitamins A, D, E, and K
Water soluble: Vitamin C and the B Vitamins - Thiamin (B1), Riboflavin (B2), Niacin (B3), Folate (B9), Biotin, Cobalamin (B12), and pyridoxine(B6)
inorganic nutrients that are needed in small amounts to keep the body healthy.
Minerals
Major Minerals and Trace Minerals
- Major Minerals, in order of quantity in the body, includes: Calcium, Phosphorus, Potassium, Sulfur, Sodium, Chloride, and Magnesium.
- Minor Minerals, in order of quantity in the body, includes: Iron, Zinc, Copper, Manganese, Iodine, and Selenium
